Hydraulic drill press



M 1 1947. J. w. KARWEIT HYDRAULIC DRILL PRESS.

Filed Nov. 6, 1943 5 Sheqts-Sheet l April 15, w w

HYDRAULIC DRILL PRESS Filed NOV. 6, 1943 5 Sheets-Sheet 2 5Y 4 3 My YINVIISN'T R. BY J92 W 02' e1 April 15, 1947.

J. W- KARWEIT HYDRAULIC DRILL PRESS Filed Nov. 6, 1945 3 Sheets-Sheet 5 w 7,. 6 W W a i 0 v U WM an 1 N 1J7 3 H /u I m Na W IF .P if fl "Hi. w M MWMW m: I I En U, Q A Y fllmul a a m m x. 3n vii/Kai, m

m Mm. V A/229 4 z a w 2 7 1w 4 I 7 a 8 5 6 6 3 a e W m Patented Apr. 15, 1947 HYDRAULIC DRILL PRESS .ltohn W. Karweit, Skokie, Ill., assignor, by mesne assignments, to Ex-Cell-O Corporation, Detroit, Mich, a. corporation of Michigan Application November 6, 1943, Serial No. 509,233

15; Claims.

The'invention relates to power driven tools and more particularly to drill presses and certain provements therein adaptable also'for use with similar tools. The present application. is a continuation-impart of my application, Serial No.

464,340, filed November 3, 1942;

up to work with one particular metal, and no other metal was to be used, it was possible to dispense with the arrangement for feeling the feed. In fact, one machine drilling only one metal all the time could be automatic. However, where the drill press would be used for a miscellany of work materials, it was necessary that the feel of the drill be provided since, under conventional practices, stringy metals such as copper, aluminum and naval brass would be encountered, i. e. where the material, including many plastics is. ductile enough that a shaving cut from the material does not break under the cutting strain imposed upon it'by a cutting edge fed into the material. Without the feel of the feed, drill breakage would be very high.

Furthermore, even where the feel of the feed is present in a hand-feed drill press or the like,

the tool breakage is high, particularly where the press is operated by inexperienced operators, or where a deep cut is to be made and the operator seeks to establish a favorable production record.

In other instances, as where a work piece, such asacarburetcr body, is nearing zompletion great care must be exercised to safeguard against breakage of tools in the work piece that would scrap: the piece. In someinstances the final cuts are made by hand. Much time isconsumed in performing the operations conventionally, and the danger of drill breakage with deep cuts is always imminent.

In the present invention not only is the prime cause of tool breakage eliminated, namely, the binding of the chips in the drill flutes, as more particularly discusse in my cc-pending applications Serial Nos'.. l55,4-l7 and 484,612, reference to which is hereby made for other and further dis-- cussion. upon this point, butthe present inven- 2 tion also provides an improvedv drill press or the like, in which the feel of the feed is not essential to the handlingor diiierent metals.

A- further object of the invention-isto provide an'improved process. and apparatuswhich, while the drill is-in operation, produces or comminutes at the cutting edges, chips which are of a regulated, substantially uniform sizeand shapefora given. drill size regardless of the material being drilled, and the-size of the chips'is socregulated as to be small enough to'clear the flutes easily, yet large enough and curled sufficiently that. chips willnot packv in the flutes.

Another object of the'inventionis. toprovide a drill whi 2h oscillates the. drill withintheteachings of, the invention. only when. thedrill= is in its work feed traverse, and. also. in which. the. distance ofthe oscillation. can be varied or adjusted during operation Another object ofr the invention is to provide an improved drill presswhich is less tiringupon the operator mentally and physically to operate, and canbe operatedsuccessfully by unskilledas well as skilledoperators.

A further object of the invention isto provide animproved hand-feeddrillpress which can be operated manually for special worker semi-automatic for production work.

One of the objects of.the presentinvention is to. provide the combination of a rotary drill and ahand forward feed in. whizh the feed traverse effort is a substantially constant factor.

Another object of the inventionis to provide an improved drill press which amateurs may use, who are unskilled mechanically, with little fear of drill breakage during deep cuts of a stringy metal or metalsand. in which the feed traverse effort can be adjusted and maintained constant.

A-further object of the invention to provide a drillpress or the like whose feed traverse characteristics'may be varied manually or automatically;

A further object-of" the invention is to provide a feed arrangement for a drill press where the rate of feed can bekept uniform automatically at any one of a plurality of feed rates, depending upon the size of out being mad'e.

Another object is to provide a drillingproc'e'ss for stringy metals and plastics in which a: single I feed traverse is limited only by the length of the flutes upon the drill.

Another obj ect of the invention is to providev a device of thee class described whichis' simple; in construction and. operation, and: inexpensive" to manufacture. and maintain These being among the objects of the invention, other and further objects will become apparent from the drawings, the description relating thereto and the appended claims.

Referring now to the drawings:

Fig. 1 is a side elevation of a drill press illustrating a preferred embodiment of the invention;

Fig. 2- is an enlarged vertical section of the upper portion of the drill head shown in Fig. 1;

Fig. 3 is an enlarged vertical section of the lower portion of the drill head shown in Fig. 1;

Fig. 4 is a section taken upon the line 44 in Fig. 2;

Fig. 5 is an enlarged side elevation of the rapid forward and feed traverse control;

Fig. 6 is a section taken upon the line 6-6 in Fig. 5;

Fig. 7 is a cross section of the spindle indicating the drive relationship provided between the sleeve and spindle;

Fig. 8 is a diagrammatical view of the hydraulic system employed in the invention.

In the practice of the invention. as further described in the co-pending ap lications referred to. the drill is preferably oscillated repeatedly a distance just enough to terminate or comminute the chips being formed as often as approximately once every relative revolution between the work piece and the drill if the drill has two cutting edges, such as a twist drill. Although the timing of the reciprocation may be varied to occur every second or third revolution if desired. the question of whether or not this is done for any particular application will depend a great deal upon the size of the chip that can be cleared by the flutes "considering the metal being machined, and upon the number of cutting edges u on the drill. It is preferred that the cutting edges overlap between foscillations and if the drill has a single cutting edge. the oscillation will preferably occur approximate v nce everv two relative revolutions. at least a revolution plus the fraction of the next revolution which represents the period of the oscillation itself, which oscilla ion is timed preferably to take no longer than 90 degrees of a rotation and less, if possible, depending upon the inertias of the mass to be moved. The distance of the oscillation is that which will cause the cutting edges to terminate the chip having in mind the additional distance needed to counteract the deflection in the drill press itself when the feed chuck l3 may be suitabl located with respect to a work piece l4 disposed upon the work table l5. Standard l l, in turn, is supported upon a base It 4 shifted to any other groove upon the pulley 25 than that shown.

The shaft 24 of the motor extends beyond the motor housing at both ends and at its lower end receives a drive coupling 30 by which the drive shaft of a hydraulic pump 32 is driven. The pump 32 is mounted by brackets 33 and bolts 34 to the lower part of the pump casing and comprises a pump compartment 35, a sump 36 and a pressure relief valve 31 by which the hydraulic fluid present in the pressure line 38 is maintained at a constant pressure, the pressure relief valve 31 being adjustabl set to relieve the line 38 to the sump above the fluid supply and pressure needed to feed any particular drill into the work piece I 4. Upon the right hand side of the support H the head In is provided with a cored enlargement 40 machined to receive the working parts that will now be described.

Within the cored enlargement 40 a. hollow shaft 4| is journalled which carries at the lower end thereof a sleeve 42 (Fig. 3), the inner surface 43 of which constitutes a pressure cylinder. The journalling of the shaft 4| is accomplished by means of a pair of frictionless bearings 44 (Fig. 2), held in place in a suitable bearing cavity 45 against a shoulder 46 by a gland nut 41 threaded into the outer end of the cavity.

The lower end of the shaft 4| has an enlargement 5! thereon received within the upper end of the sleeve 42. The upper rim of the sleeve 42 is upset as at 52 around the inner shoulder of the head 5! where it is brazed as at 53 to the reduced portion of the shaft 4| beyond the head 5| to provide a shoulder against which rests the inner race of the lower one of the two bearings 44. With this arrangement upward thrusts exerted by the sleeve 42 are borne by the gland nut 41 and a driven pulley 55 is secured to the shaft 4! where it extends above the gland nut 41 by means of a Woodrufi key 55 and a set screw 51.

At its lower end the sleeve 42 is journalled in the bearing cavity 58 by means of a frictionless secured to a floor or table I? by bolts l8. Means .for supplying lubricant or coolant for the drilling operations is shown at 9.

As viewed in Fig. 1, a motor 20 is mounted to .the left of the standard H upon a base member 21 which is pivoted as at 22 to an adjustable carrier 23. The drive shaft 124 of the motor is permits the motor to be pivoted about a horizontal axis to release the belt inevent the belt is to be hearing 60 held in place by a bearing retainer 6| threaded into the lower end of the enlargement 48. The lower end of the member 42 is flanged outwardly as at 62 and tapped longitudinally as at 53 to receive the ends of the bolts 64. The included shoulder 65 of the flange rests against the inner race 56 of the bearing 60 and a seal El is disposed between the enlargement 40 and the sleeve 42 as held in place by a gland washer 68 assembled ahead of the outer race of the hearing 30.

A driven shaft Hi having a splined outer face, as sectionally shown in Fig. 7, is received in the cylinder 43 of the sleeve 42 where it is supported at the upper end by a piston head i! having a seal 12 on the top thereof held in place by a bolt 13. The rotary drive between the sleeve 42 and the shaft 10 is accomplished at the lower end of the sleeve 42 by means of splined female runner 14 for the shaft 70 locked in place by the .bolts 64 with alternate washers l5 and seals [6 held in place around and in the splines of the shaft where the shaft 78 extends beyond the runner l4.

With this arrangement, whenever a hydraulic fluid under pressure is supplied to the cylinder 43 through abore Tl provided for that purpose longitudinally through the shaft M, the shaft 10 is forced downwardly to provide a forward or feed traverse for the chuck 13 that is supported con- -ventionally on the lower end of the shaft 70 by means of a shank 78 received in a taper 8%. Re-

Versepn'returntraversei ofithe'shaft I 0. is:accom:---

plished:i.by'"app1ying: a-x counter" hydraulic fluid DI'ESSUIGFtO thetcylinden 43- below-the. head" I I j as by? aipassageway' 81I drilled: through the enlargement/:40 of the: head I to. a: recess-82 inithe inner wall. from" whence" the; fluid reaches the interior of the sleeve 42 through'perforations 335 provided in the sidewall thereof? where :they register with the. groove 82.

Withthedescription thus" far; it' will be understoo'dhow'thedrill'chuck I3 and a drill 48; car ried .thereby,.is.=rotated bythe motor 20 through the beltzzfi andraised and lowered bodily by means .ofi'alternatelyapplying the-hydraulic fluid pressure. developed by the pump 32 above and below the7plsl30n. I I in the 'cylinder 43.

The control? of the piston. will. now be described'z;

Referring to Fig. 2, the shaft 4| receives: a rotary cylindrical valve memberllil thereon between thebearings' ll l wherethe head is enlarged to'proyide av cylindrical valve compartment 88;

. The. valve member is' secured to the shaft bymeans-"of. a pin 50 which; if desired, can extend clear" through. the valvemember' for: ease in assembly; Passages inthe valve member open upon the cylindrical surfaceato cooperate with valve ports: opening" upon. the: inner? face of i' the valve compartment as willinow be described;

Aslaid'; outfflatin-Fig: 8,- the; surface of the valve member" is provided with three circumfer enti'ally disposed grooves axially spaced from each other; The" groovesare in communication with the. cylinder 43 through" bores 94 opening into the. bore: I'IZ' The upper'groove: 92 extends for. approximately 300 of the: circumference in one plane: asat? I00' and" angles downwardly-rte another plane where; it? extends in. a spur IOI; approximately 3001. the remaining: 60.. The

long portion I llfizregisters' with aport I08, upon thet compartment-wall and the. spur. I ii I. registers with'a'porti I ilzupon the compartmentiwall.

Through. the valve housing" 95 a: passageway I I'll is' drilledztoopenupon' the face: 93 at the port1I08 which registers-with the. groove92. in' the rotary: member; The flow of: hydraulic? fluid through the passageway IE1 is controlled by means of a: needle valve I'IIl asrsupplied with hy-' drauiic fluid under pressure from the: line; II.I=. With this arrangement of the'groove- 92," andport I03, the supply of 'hydraulic'fluid to thecylinder 43 is intermittent in' quantities controlled? by the needle valve I ID. More specifically, each time the chuck and drill'I3" revolves the groove 92 and port I08 are. incommum'cation: with. each other throughout approximately 3.00" of the rotation; and; out of communication with each other throughout the remaining portion of relative rotation. Hydraulic fluid is supplied to the chamber 43. in quantities metered bythe needle valve .I I0 duringthetime the groove. 92 and port I 08 arein communication with each other,. and this: supply is: interrupted when the; groove 9.2 and port I08 are movedto relative positions out of: communication with each other; With this control; the drill it-risintermittently. fed intothe work: to cutsome-metal for: the work? in a series of successively identical steps timed in relatiomv ship to'therotation ofthe drill in the work.

Through the: valvehousing 95 a passageway I03." is drilled: to open; upon: the: face: 93- at; the port I02 whichregisters withztheispur llll'k The flow of hydraulic? fluid? through: the; passage N33 is: controlled by means: ofia" needle valve I94: as suppliediwitnhydraulic.fiuidunderrpressurefrom thez-lineell I: with'rthisaarrangement ofrthegsnwz:

I01I: and port". I02; thessupply 0f.:hydraulic:fiu id under :pressure to: the cylinder 43.is; intermittent in quantities- -controlled by the needle; valve I043 Moreyspecificallmgeach time thepchuck. l3'and drill 48 revolve; the; spur" I III- andpOrt-AUZ" are in communication-with each other" for approximately 30- of; rotation beforethegroove. 92: and port I08 are brought: into communicatiomthe direction of rotation of thEiVE/IVG being-indicated by "the arrow' I 05.:

A: second' groove is:' indicated at. 9I extending the full-360 of-the-valvei. Hydraulic fiuidzunder; pressureymay also be supplied to thecylinder: 43 above the. headTI through-thegroove 91 which is -in continuous registration with an opening: I I 2 to;v receive fluid fromgther 11118: H 3i In. this way-.5 by selecting; which. of; thetwo. conduits: III or 3 is to supply hydraulic. fluid ;,to the cylinder 43; the piston I I may be'alternatively subjected. to. a mete red intermittent fiow-or an uninterrupteed: flow. This selectionzis made. by means of; a valve: I1l 4= located inawalve housing I I 5- fastened to the head. I II: asby a:- split collarilfiaand arbolt I I1.

A third groove I06, located below andiina plane separatefrom1the groove I00; III-I communicates with. a port: I 09* for: approximately 30 of rotationofthewalve and during theitime that the-groove 924s out ofi'communication with the. ports; I 02 2116.158; The. port; I 09; isgin. comm-uni: cationwith aconduit .lIirleading to the1valve; I,I4 when the. conduit QGTiS' placed;incommunicatiorr with the sump 3B, passageway 95".: inithe; valve. 5 I 4; andithe;pipe-.9 8. Thus; for approximately 30 of rotation, the cylinder;43 :is. in com-municaetion with;the*sump.

It ispreferred that thegrva-lve I ld/beycontrolled automatically and adjustablyw in relationship to the position-oftthe piston-VII in the; cylinder-43,; the-valvebeing: disposed to provide an; uninterrupted flow to the cylinder 43rto provide-ia rapid forward traverse,- untilthefeed'traverse station is reached, atwhich time. the. intermittent-mertered supplies of hydraulic liquid is; substituted to provide.- the feed. traverse discussed, and the conduit 96- placed, in communication withzthe sump through the valve passage 91.

It might be mentioned. at this time that during the. work feed'of the drill, the third groove permits retraction of the piston to behad. during 30 of each. revolution, as, controlled by the valve 9 9 to terminate a chip being" formed, the meter:- ing, valve-I04 provides; a brief heavy supply of hydraulic. fluid; to recover. the, retraction permitted tothe-piston and forrthe remaining. 300; the-piston is forward fedat a feed traverse to start and out another chip from the work piece.

The transition from the rapid forward traverse to. the. feed traverse. forthe. purposes discussed of; a slidfrr I24 which. can. be; clamped in.place by a winged nut I26.

For; purposes of. actuating the valve-by vertical movement: of; the dog I20 an L-s'hapedarmg I21 is mounted upon the outer end of the valve: H4 0 with; one. of thearms being engaged by and moved. by: the dog: I 29. when'the dog moves. down:-

ward'lyv to: the: position" shown in phantom I28; and 17 06? other: of the: arms; being engagedi'bythedogs I .ZII; when. the .dogiszmoved. from. its, position- I28; to. its full. line: position; as. shown imEig;

As'the dog I 20 moves downwardly, it yields inwardly, supported by springs I30, to the degree necessary to clear with close contact the arm I21. Pins I3I are provided to support the dog I20 in sliding relationship with respect to the follower I24 to provide for the yield described.

In the position of the valve shown in Fig. 8 the valve is the same as that shown in Fig. wherein the port I32 leading to the line H3 is in communication through the valve passageway I35 with a fluid supply line: I33 and its port I34 and conduits 96, 38 are closed. In this position the piston II is moved downwardly by a constant and uninterrupted supply of hydraulic fluid under pressure in the supply line I33 until such time as the dog I20 contacts the arm I21 to move the valve to its alternative position in which passageway 91 opens communication between conduits 96 and 98, and, the valve port I36, communicating with the line III, is placed in communication with the passageway I35 and the port I34 through the T passage I31 in the valve II4. In this position the piston II is subjected to the intermittent metered feed provided when the cylinder 43 is connected to the line III, as described.

The operator controls the supply of hydraulic fluid to the conduit I 33 by means of a two-position valve I40. As more particularly shown in Fig. 3, the pressure line 38 is placed in communication with the supply line I133 through a slot I4I cut in one side of the valve I40 where it will register with the ports I42 and I43 for the lines 38 and I33, respectively.

Theline leading back to the sump 3B is indicated at I45 and in the position of the valve shown in Fig. 3 the space in the cylinder 43 below the piston II is placed in communication with the sump line I 45 through the port I46 by means of a slot I41 upon the other sideof the valve which establ shes communication between the lines 8I and I45.

Between the l ne BI and the cylinder ports 82 and 83 is located a bifurcated passage I54 in one branch of which is a check valve I55 open ng inwardly to admit flow of'hydraulic fluid into the cylinder 43. In the other branch a piston relief valve I56 is mounted opening with the flow of hydraulic fluid from the cylinder 43 as controlled by a heavy spring I5'I adjusted as to tension by the adjusting nut I58.

'Retraction of the p ston II is accomplished by the piston valve I56 which yields to'release hydraulic fluid from the cylinder under the superior pressure provided above the piston during 330 of the rotat on. Then when the ports I 09 and I06 register to place the cylinder 43 in communication with the sump 30, the piston valve I56 closes and under the urge of the spr ng forces some of the hydraulic fluid ahead of it back into the cylinder 43 as a counterforce below the piston 'II' to the extent permitted by the valve 99 after which the retraction of the. piston thus induced is recovered by the extra supply of hydraulic fluid provided immediately thereafter through the metering valve I04. 7

Furthermore, the back pressure efiect of the piston valve I56 has a steadying effect upon the system.

After the rapid forward traverse has been accomplished and the feed traverse allowed to proceed until the drill cuts to the distance desired, the valve I40 is rotated counter-clockwise to the position shown in phantom I48 in which the port I42 of the pressure line 38 is placed in communication with the cylinder below the piston through the line 8I to force the piston upwardly and provide a rapid reverse traverse for the drill, and the cylinder 43 above the piston 'II is drained back to the sump by the port I43 and the supply line I33 being placed in communication with the port I 45 leading to the sump line I45.

However, since upon the reverse stroke of the piston II the cylinder 43 above the piston is still in communication with the supply line I33 through the needle valve IIIl, I provide a by-pass for the valve H4 in the form of a conduit I50 connected to the conduit II3 by means of a T fitting i5I. The other end of the conduit I50 is adapted to be placed in open communication with the sump line I45 through a bore I52 cooperating for that purpose with the valve slot I4 I.

The position of the valve I40 is determined selectively by the operator by means of a handle I53, the construction and the movement of the handle being so correlated that forward traverse and oscillation feed movement of the drill is established when the handle is moved downward and the reverse traverse of the drill is accomplished when the handle is moved upwardly. The valve I40 closes the bore I52 when the handle is in its down position, thereby permitting the valve I I4 to funct on in the manner described.

The valve H4 and dog I20 are further constructed and arranged so that when it is desirable to feed the drill or some other tool into the work without benefit of the metered intermittent supply of flu d, it can be done by the dog I20 being removed from a position actuating the valve H4. Manipulation of the handle I53 is then relied upon to regulate or meter the fluid supply through the port I43 to the supply line I33 and the line H3. In this way, the device not only can be used to drill with a chip breaking action, but also can be used as any other standard drill.

On the other hand, by incorporating another dog I20 upon the shaft I2I to actuate the valve I40 at the lower limit of the feed, the drill press can be made to operate fully automatically after a forward traverse is initiated. With this arrangement (not shown) the second dog I20 would move the valve I40 from its forward traverse position, as shown in Fig, 3, to its alternate reverse position, shown in phantom I48, it being understood that suitable feed limit stops could be provided or arranged to determ ne the depth to which the drill is fed into the work I4.

Operation Presupposing that the motor 20 is rotating with the handle I53 disposed in its upper position, a pressure is built up in the pressure line 38 to the degree determ ned by the relief valve 37 and hydraulic pressure is applied to the cylinder 43 below the piston H, where the drill 48 and drill chuck I3 are held at their upper or retracted limit.' Then, when the handle I53 is moved to its downward position, pressure in the line 38 is supplied in full measure to the cyl nder 43 through the supply line I 33, valve conduit I35, and groove QI to provide a rapid forward traverse for the drill 48 until the dog I20 contacts the arm I2? and moves the valve II4 to its alternate position in which the fluid supplied by the sup ply line I33 is applied through the conduit III to the cylinder 32 as-metered by the needle valve IIO and interrupter valve 90. In event the drill 48 is of small diameter the metering valveIIB is adjusted to a minimum flow, whereas if'the drill in the chuck I3 .is of. large diameter the a rees;

valve l H1 is adjusted to a greater flow, the valve being operatedby a handle assembled through a suitable opening Ifil in the casing EBB employed to shield the parts from damage.

During the remainder of the feed traverse, the Valve 90 subjects the piston to periodic oscillation in which the piston is fed forward for 300 by hydraulic fluid supplied by the feed traverse valve llll, then retracted for 30 by the piston valve I56 when the valve ports IE6 and ifiil register and are in communication with the sump, and retracted distance recovered by extra hydraulic fluid supplied through the recovery valve I04.

This distance of retraction is governed by the valve '99 in the conduit sump line 96 and the recovery of the retraction is controlled by the recoveryvalve I84. During retraction, the chips being formed are terminated and with 'a series of oscillations accomplished as described, the chips are cut to uniform size small enough to clear the flutes-easily, yet large enough as not to pack in the flutes. During the feed traverse cooling lubricant is supplied to the drill and work piece to keep the drill cool as described in my copending applications.

After-the piston II has been fed forward to carry the drill to the proper depth, the handle I53 is raised manually or automatically to its upper position, at which time the cylinder 43 above the piston is placed in communication with the sump through the conduit H3 and by-pass I50. Fluid under pressure is supplied below the piston?! through the conduit 8| to force the piston upwardly.

The reverse traverse will "be faster than the rapid for'ward traverse since the displacement of thepiston H is'greaterforthe same amount of fluid below the piston as compared with the same amount of fluid above the piston, the piston in other words constituting a differential arrangement.

Whenever the valve H4 is leftin the position showninFig. Band Fig. '2, as by removing the dog l 2fl'froma position actuating the arm I21, the feed movement of the drill is controlled" by the handle 'l53,'same being a smooth forward fe'e'd anda smooth reverse traverse, the'speed'of which-isregulated by the degree of communicationper-mitted by the valve I40 between'the respective ports in relationship to the position of the handle.

In eventadrill is used-havinga single cutting edge, it is desirable to rotate the work piece against the drill at approximately the same speed as the drill so that the cuts of the drill overlap between oscillations, thereby removing the material left by 'apreceding out before leavin'gmaterial again at-the next oscillation.

(Having-thus described the invention, the mannereinwhich the objects are accomplished will be understood more clearly when it is noted that with the present invention, regardless of the metal being out by the drill, all the chips come out=a uniform size, a size that can be determined bythe length of the arcuate ports 92 and 92a, and the degree of feed permitted to exist by the adjustment of the valve H0, it being possible with this arrangement to provide chips small enough to readily clear the flutes in the drill and be handled thereafter in much the same manner that 'one would handle sand, as distinguished from long curls and stringy chips that would otherwise bind inthe drill and cause drill breakage.

Consequently, 1 although :certain "embodiments of the invention have been shown and described therein, it will be apparent to those skilled in the art that other and'various modifications oi the invention'may be made without departing from the spirit of theinvention, the scope of which is commensurate with the appended claims.

'What is-claimed is:

1. 'In a power driven 'drillpress'the combination of rotary drive and drivenmembers, a cylinder-connectedto one of the members, a piston connected to the other member and located in the cylinder, means upon'the driven member for receiving a drill in working position to drilla work piece, means for supplying'hydraulic fluid to said cylinder upon one side of the piston to feed traverse the driven member and drill with respect to the workpiece including a valve-relaxing theflow of hydraulic'fluid momentarily once each approximaterevolution,and-means for sunplying hydraulic'fluid under pressure to the cylinder upon the otherside of the piston during the time when said flow is relaxed.

2. Ina 'powerdriven dril1 press the combination of rotary drive 'and driven members, a cylinder connected to'one of the members, a piston connected to the other member and located in the cylinder, means upon the driven member for receiving a drill in working position to drill "a work piece, means for supplying'hydraulic fluid to said cylinder upon one side of the piston to ieedtraverse the driven member and drill with respect to the work piece including a valve relaxingthe flow of hydraulic-fluid momentarily once each approximate revolution, means for supplying hydraulic fluid under pressure to the cylinder upontheotherside of the piston during'the time when said'flowis relaxed, toretract the drill a distance -sufficient "to terminate the chip being formed-by the drill, and means ior-supplying L0 said -one-side of the cylinder suiflcient fluid for the piston'and drill torecover the distanceretracted between the" time the flow is first relaxed and the feed' traverse is again resumed.

"3jlna power driven drill press the combination of rotary driveand driven members, a cylinderconnectedto one of the members, a piston connected'to the other "member and located in the-cylinder, means upon the driven member for receivingadrill in position to drill a'work piece, means for rapid forward traversing the driven member and drill to -a predetermined position away from a'resting position, means for supplying hydraulic'fluid tosaid cylinder upon one side ofthe piston to feed traverse the driven member and-drill with respect to the work piece from said predetermined position including a valve relaxing the flow oi hydraulicfluidmomentarily once each approximate revolution, and means for supplying hydraulic fluid under pressure to the cylinder upon the other side of the piston whenever said flow is relaxed to lift thedrill enough to terminate the chip formed by the-drill thereto.

'4. In a power driven drill press the combination of rotary drive and driven members, a cylinder connected to one 'of the members, a piston connected tot-he'other member and located in the cylinder, "means upon the driven member forsuppor'ting "a drill in working positionya' valve 'means'driven by one of said-members having'a first pairof ports in registerduring the-major portion of each revolution of the drill,- a second pair of ports brought into register with each other-during a portion of each revoanew 'lution' following said major portion, a third pair of ports brought in register during the remaining portion of each revolution, said first pair of ports placing the cylinder in communication upon one side of the piston with a source of metered hydraulic fluid under pressure, the second pair of ports placing the cylinder in communication upon the same side of the piston with a fluid pressure relieving conduit, the third pair of ports placing the cylinder in communication upon the same side of the piston with a source of hydraulic fluid under pressure having a flow characteristic greater than the first source, and means for applying fluid under pressure to the cylinder upon the other side of the piston when said second pair of ports arein register.

5., In a power driven drill press having a head and work support, the combination of a plurality of axially aligned elements, means for reciprocating said elements with respect to each other including a cylinder connected to one element and a piston connected to the other element and disposed in the cylinder, means for rotating one of the elements, means for supporting a machine tool drill having a cutting edge thereon, means for introducing fluid under pressure into said cylinder for traversing said element and drill at a feed traverse including a device intermittently interrupting the supply of fluid under pressure after the cut of the cutting edge overlaps the point where the cut was begun,- and means for oscillating said one element and supported drill with a reverse traverse within a minor portion of a revolution a distance just enough for the cutting edge to terminate the chip being formed during each interruption of said supply of fluid under pressure.

6. In a device of the class described for machining a work piece, a housing, a drive shaft, and a driven shaft, said driven shaft comprising two members journalled in the housing and movable axially with respect to each other, a hydraulic element for moving said two members axially with respect to each other to provide a feed traverse, and means controlled by one of said members for controlling said element to retract said members momentarily in stepped relationship with the rotation of said members during rotation, and a drill carried by one of said members for drilling a work piece, said retraction lifting the drill to comminute the chips formed by the drill.

7. A drill press having a head and a work table, a plurality of axially aligned shafts, means for moving said shafts longitudinally with respect to each other including a cylinder upon one shaft and a piston carried by the other shaft disposed in the cylinder, means for rotating the shafts simultaneously, means for mounting a drill on one of the shafts, means for introducing fluid under pressure into said cylinder for moving one shaft longitudinally with respect to the other, and means countering said fluid under pressure for reciprocating said shafts in a reverse direction momentarily within a minor portion of a revolution to comminute at the cutting edge of the drill the chips formed by the drill.

8. A drill press having a head and a work table, a plurality of axially aligned shafts, means for moving said shafts longitudinally with respect to each other including a cylinder upon one shaft and a piston carried by the other shaft disposed in the cylinder, means for rotating the shafts simultaneously, means for mounting a drill on one of the shafts, means for introducing fluid under pressure into said cylinder for longitudinally moving one shaft with respect to the other, and means countering said fluid under pressure for reciprocating said shafts in a reverse direction momentarily once approximately every one to three revolutions of the drill to comminute at the cutting edge of the drill the chips formed by the drill.

9. A drill press having a head and a Work table, a plurality of axially aligned shafts, means for moving said shafts longitudinally with respect to each other including a cylinder upon one shaft and a piston carried by the other shaft disposed in the cylinder, means for rotating the shafts simultaneously, means for mounting a drill on one of the shafts, means for introducingfluid under pressure into said cylinder for moving one shaft with respect to the other to provide a feed traverse, and means for momentarily reciprocat ing said shafts reversely a distance suficient to terminate the chips formed by the drill and as often as once approximately every one to three revolutions of the drill in its feed traverse.

10. A drill press having a head and a work table, a plurality of axially aligned shafts, means for moving said shafts longitudinally with re spect to each other including a cylinder upon one shaft and a piston carried by the other shaft disposed in the cylinder, means for rotating the shafts simultaneously, means for mounting a drill on one of the shafts, means for introducing hydraulic fluid under pressure into said cylinder for moving one shaft with respect to the other, and means driven by one of said shafts for intermittently interrupting the supply of fluid under pressure to said cylinder and retracting said one of the shafts slightly once each revolution and including a flow interrupting valve and a flow metering device,

11. A drill press having a head and a work table, the combination of a plurality of axially aligned shafts Journalled in the head, means for reciprocating said shafts with respect to each other including a cylinder upon one shaft and a piston carried by the other shaft disposed in the cylinder, means for rotating the shafts simultaneously, means for connecting a drill to one of the shafts, means for introducing fluid under pressure in said cylinder for moving one shaft with respect to a work piece, and means driven by one of said shafts for intermittently reversing the supply of fluid under pressure to said cylinder after the said one shaft has approached to within a predetermined distance of a work table to lift the drill once each approximate revolution approximately the thickness of the chip being formed.

12. A drill press having a head and a work table, the combination of a plurality of axially aligned shafts journalled in the head, means for reciprocating said shafts with respect to each other including a cylinder upon one shaft and a piston carried by the other shaft disposed in the cylinder, means for rotating the shafts simultaneously, means for connecting a drill to one of the shafts, means for introducingfluid under pressure in said cylinder for moving said one shaft with respect to a work piece, and means driven in stepped relationship with one of said shafts for intermittently reversing the supply of fluid under pressure to said cylinder once each approximate revolution after the said one shaft has approached to within a predetermined distance of a work table, and means for by-passing 13 said driven means when said one shaft is moved away from the work table.

13. In a drill press having a head and a work table, the combination of a plurality of axially aligned elements, means for reciprocating said elements with respect to each other including a cylinder up on one element and a piston carried by the other element disposed in the cylinder, means for rotating one of the elements, means for connecting a drill to said one of the elements, means for introducing fluid under pressure in said cylinder for traversing said one element towards said work table, and means driven in stepped relationship with said one element for intermittently interrupting the supply of fluid under pressure to said cylinder and reversing momentarily said traverse.

14. In a power driven drill press having a head and a work support, the combination of a plurality of axially aligned elements, means for reciprocating said elements with respect to each other including a cylinder upon one element and a piston carried by the other element disposed in the cylinder, means for rotating one of the elements, means for connecting a drill to said one of the elements, means for introducing fluid under pressure in said cylinder for traversing said one element towards said work table at a rapid forward traverse, means driven in stepped relationship with said one element for traversing said one element at a feed traverse following said rapid forward traverse including a device intermittently interrupting the supply of fluid 14- under pressure to said cylinder once each approximate revolution, and means for reverse traversing said one element each interruption a distance of approximately the thickness of the chip being formed by the drill.

15. In a device of the class described for machining a work piece, a housing, a drive member, a driven shaft, said driven shaft comprising two members journalled in the housing and movable axially with respect to each other, fluid pressure means for moving said two, members axially with respect to each other in feed traversing direction including a hydraulic element, means upon one of said members for carrying a drill for drilling a-Work piece, and means for oscillating said one ofthe members and the drill carrying means with a reverse traverse once each approximate revolution which oscillation is accomplished Within a minor portion of a revolution a distance enough to terminate the chip formed by a supported drill immediately prior thereto.

JOHN W. KARWEIT.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,911,132 Macomber May 23, 1933 1,759,412 Noble May 20, 1930 2,324,374 Eden July 13, 1943 

